Gas prices fall, but look out

ATLANTA (CNN) -- Gas prices fell 2 cents over the past two weeks, to a national average of $2.79 per gallon of self-serve regular, according to a survey published Sunday.

But drivers should expect that direction to reverse course soon, said Trilby Lundberg, publisher of the Lundberg Survey, which tallies prices at about 5,000 stations every two or three weeks.

The modest drop in prices between the survey dates of Sept. 7 and Sept. 21 "is only a blip in the price climb," she said.

That's because, on a per-gallon basis, the price of crude rose nearly 12 cents per gallon during the two-week period. "High crude oil prices have replaced refinery problems as the big gasoline price-change factor," she said.

So, why don't drivers see that increase reflected in higher pump prices?

"It's hiding in temporary losses in profit margins for refiners and retailers," Lundberg said. "Both sectors ate that loss."

But, she predicted, "that bottleneck will be very short-lived ... there is at least five to 10 cents on its way to the pump, and soon."

That outcome could be reversed only by a steep drop in the price of crude, "which is not a reasonable expectation right now," she said.

Drivers in Newark, N.J., a state that has no self-service but does have low taxes, paid the least on average, at $2.51 per gallon of self-serve regular; drivers in Chicago paid the most, at $3.16.

Here are the average prices in some other cities: Atlanta: $2.73; Denver: $2.78; Honolulu: $3.09; Long Island, N.Y.: $2.85; Providence, R.I.: $2.66; Seattle: $2.88; San Diego: $2.94.